A lithium ion battery is an ideal power source for a modern vehicle because of the advantages of non-pollution, low cost, high capacity, long cycle of life, etc. The lithium ion battery is typically formed by winding or stacking a positive plate, a separator and a negative plate sequentially to form an electric core, placing the electric core in a chamber formed by a battery shell and a cover plate, injecting an electrolyte in the chamber, and sealing an opening end of the battery shell, followed by formation. In the lithium ion battery, whether the sealing by the cover plate is good may affect battery safety, aging resistance and insulating performance of the lithium ion battery. In addition, the cover plate accounts for a certain proportion of the total cost of the lithium ion battery. Production efficiency and improvement of yield of the cover plate may help reduce the cost of the battery.
Currently, the sealing and insulation of the lithium ion battery are mainly realized by injection molding a plastic. Meanwhile, a ceramic sealing member may be used for insulating and sealing the cover plate. However, ceramic is difficult to weld and easy to break or crack, so the ceramic is only restricted to be used as a ceramic gasket. And other conventional sealing members, such as a plastic sealing member, may still be required for the sealing between the cover plate and an electrode terminal. When a ceramic sealing member is used for insulating and sealing between the cover plate and the electrode terminal, due to material differences, large stress produced during the welding process may break or crack the ceramic sealing member, and thus decrease the reliability and stability of the battery, reducing safety of the lithium ion battery, increasing manufacturing difficulty, reducing battery yield, and affecting practical applications and development of the battery.